Difference between revisions of "Constant"
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{{Constant}} | {{Constant}} | ||
| − | A '''constant''' is a variable that does not change, it has a | + | A '''constant''' is a [[Variable|variable]] that does not change, it has a final value. |
| − | Constants are defined in the [[Const#Const_Section|const]] | + | Constants are defined in the [[Const#Const_Section|<code>const</code> section]] of a [[FPC|Free Pascal]] [[Program|program]]. When a symbol is defined as constant, the [[Compiler|Free Pascal compiler]] can often do some optimizations to make the output code faster or smaller. |
| − | Some special Free Pascal constants: | + | |
| + | Some special Free Pascal constants are: | ||
Logical truth values | Logical truth values | ||
| − | * [[False]] | + | * [[False|<syntaxhighlight lang="pascal" inline>false</syntaxhighlight>]] |
| − | * [[True]] | + | * [[True|<syntaxhighlight lang="pascal" inline>true</syntaxhighlight>]] |
| − | + | data type limits | |
| − | * [[ | + | * [[Nil|<syntaxhighlight lang="pascal" inline>nil</syntaxhighlight>]]: empty [[Pointer|pointer]] value |
| + | * [[maxint|<syntaxhighlight lang="pascal" inline>maxint</syntaxhighlight>]]: largest possible [[Integer|<syntaxhighlight lang="pascal" inline>integer</syntaxhighlight>]] value | ||
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| − | |||
| − | == | + | The mathematical value [[Pi|π]] is realized as a function in {{Doc|package=RTL|unit=system|identifier=pi|text=<syntaxhighlight lang="pascal" inline>system.pi</syntaxhighlight>}}. |
| − | |||
| − | |||
| − | [[ | + | == See also == |
| − | [[ | + | * [[Const|<syntaxhighlight lang="pascal" inline>const</syntaxhighlight>]] |
| + | * [[Basic Pascal Tutorial/Chapter 1/Constants|Constants]] | ||
| + | * [[Class constants]] | ||
Latest revision as of 21:53, 23 February 2023
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A constant is a variable that does not change, it has a final value.
Constants are defined in the const section of a Free Pascal program. When a symbol is defined as constant, the Free Pascal compiler can often do some optimizations to make the output code faster or smaller.
Some special Free Pascal constants are:
Logical truth values
data type limits
The mathematical value π is realized as a function in system.pi.
